Myoung Ock Ahn

Nucleated red blood cells: A marker for fetal asphyxia?

OBJECTIVE Our purpose was to determine whether a relationship exists between the presence of nucleated red blood cells, hypoxic ischemic encephalopathy, and long-term neonatal neurologic impairment. STUDY DESIGN Nucleated red blood cell data from 46 singleton term neurologically impaired neonates were compared with cord blood nucleated red blood cells of 83 term nonasphyxiated newborns. The neurologically impaired neonates group was also separated as follows: nonreactive, nonreactive fetal heart rate from admission to delivery; tachycardia, reactive fetal heart rate on admission followed by tachycardia with decelerations; rupture, uterine rupture. The first and highest nucleated red blood cells value and the time to nucleated red blood cells disappearance were assessed. RESULTS The neurologically impaired neonates group exhibited a significantly higher number of nucleated red blood cells per 100 white blood cells (34.5 +/- 68) than did the control group (3.4 +/- 3.0) (p < 0.00001). When the neurologically impaired neonates are separated as to the basis for the neurologic impairment, distinct nucleated red blood cell patterns were observed. Overall, the nonreactive group exhibited the highest mean nucleated red blood cell (51.4 +/- 87.5) count and the longest clearance times (236 +/- 166 hours). CONCLUSION In this limited population, nucleated red blood cell data appear to aid in identifying the presence of fetal asphyxia. When asphyxia was present, distinct nucleated red blood cells patterns were identified that were in keeping with the observed basis for the fetal injury. In general, the closer the birth was to the asphyxial event, the lower was the number of nucleated red blood cells. Thus our data suggest that cord blood nucleated red blood cells could assist in the timing of fetal neurologic injury.

Intrapartum Doppler velocimetry, amniotic fluid volume, and fetal heart rate as predictors of subsequent fetal distress. I. An initial report.

This study examines the usefulness of umbilical artery Doppler velocimetry, amniotic fluid volume assessment, and fetal heart rate data in the early intrapartum period as predictors of subsequent fetal distress. A total of 109 patients seen in the latent phase of labor in the labor and delivery area were studied. Both an abnormal initial fetal heart rate and an amniotic fluid index less than or equal to 5.0 cm were associated with a significant increase in the incidence of intrapartum fetal distress. Conversely, a systolic/diastolic ratio greater than 3.0 by Doppler ultrasonography was not associated with increased fetal morbidity. Overall, the sensitivities, specificities, and positive predictive values of the fetal heart rate tracing and the amniotic fluid volume assessment were comparable. Doppler systolic/diastolic ratios showed very poor sensitivity and positive predictive value. We conclude that the fetal heart rate tracing or the assessment of amniotic fluid volume in the early intrapartum period are reasonable predictors of subsequent fetal condition. The lack of patients with the absence of or reverse umbilical velocity preclude conclusions with regard to Doppler systolic/diastolic ratios for this purpose.

Neonatal nucleated red blood cell and lymphocyte counts in fetal brain injury

Objective To determine whether neonatal lymphocyte or nucleated red blood cell (RBC) counts can be used to date fetal neurologic injury. Methods Singleton, term infants with hypoxic-ischemic encephalopathy, permanent neurologic impairment, and sufficient laboratory data were divided into two groups: infants with preadmission injury, manifested by a nonreactive fetal heart rate (FHR) pattern from admission until delivery; and infants with acute injury, manifested by a normal FHR pattern followed by a sudden prolonged FHR deceleration. Lymphocyte and nucleated RBC values were compared with published high normal counts for normal neonates: 8000 lymphocytes/mm3 and 2000 nucleated RBCs/mm3. Results The study population consisted of 101 neonates. In the first hours of life, lymphocyte counts were elevated among injured newborns, and then the counts rapidly normalized. Brain-injured neonates were 25 times more likely to have a lymphocyte count greater than 8000 than were normal neonates (54 [62%] of 87 versus 6 [7%] of 84; odds ratio 25.5; 95% confidence interval 8.8, 80.1; P < .001). The mean lymphocyte count tended to be higher in the pread-mission-injury group than in the acute-injury group. In comparison, nucleated RBC values were not correlated as strongly with neonatal hours of life; nucleated RBC counts tended to be higher and persist longer among neonates with preadmission injury than among those with acute injury. Conclusion Compared with normal levels, both lymphocyte and nucleated RBC counts were elevated among neonates with fetal asphyxial injury. Both counts appear to be more elevated and to remain elevated longer in newborns with preadmission injury than in infants with acute injury. However, the rapid normalization of lymphocyte counts in these injured neonates limits the clinical usefulness of these counts after the first several hours of life.

Acute fetal asphyxia and permanent brain injury: a retrospective analysis of current indicators

OBJECTIVE To determine whether a term neonate who has had sufficient intrapartum asphyxia to produce persistent brain injury will manifest the following four criteria: profound acidemia (arterial pH <7.00), an APGAR score < or =3 for 5 min or longer, seizures within 24 h of birth, and multiorgan system dysfunction. METHODS Singleton, liveborn, neurologically impaired neonates > or =37 weeks gestation who lived at least 6 days and had sufficient documentation of current intrapartum asphyxia criteria were retrospectively analyzed. Of these infants, solely neonates with acute fetal asphyxia due to a sudden prolonged FHR deceleration that lasted until delivery from a catastrophic event, e.g., uterine rupture, cord prolapse, were included. Organ system dysfunction was defined by separate criteria for each organ system. Dysfunction in one or more was defined as multiorgan system dysfunction. RESULTS Of the 292 eligible infants in the registry, 47 satisfied the entry criteria. In these 47 neonates, 10 (21%) satisfied all 4 criteria for intrapartum asphyxia. CONCLUSIONS Our retrospective study suggests that currently used indicators to define permanent fetal brain injury are not valid.

Antepartum fetal surveillance in the patient with decreased fetal movement

Whenever a patient has the subjective perception of decreased fetal movement, prompt evaluation in the form of antepartum fetal surveillance has been undertaken. The purpose of this report is to describe our experience with 489 pregnant women who came between Jan. 1 and Dec. 31, 1985 to our Antepartum Fetal Surveillance Clinic with this complaint alone or in association with another indication for fetal surveillance. Overall, 838 nonstress tests were performed, and the results were reactive, 93.2%; nonreactive, 6.8%; and fetal heart rate decelerations, 6.1%. Comparison of the first nonstress test results between those with decreased fetal movement alone or in combination with another diagnosis demonstrated a similar incidence of nonreactivity and fetal heart rate decelerations. In those patients whose indication was decreased fetal movement alone, there was a 3.7 times greater likelihood of diminished amniotic fluid volume. When the last test within 7 days of delivery was analyzed, the decreased fetal movement alone group had a lower incidence of cesarean delivery, cesarean delivery for fetal distress, and Apgar scores less than 7 than patients with an additional indication for testing. In summary, decreased fetal movement continues to be an acceptable indication for fetal surveillance. Based on our retrospective experience, the most reasonable approach appears to be a combination of nonstress test and amniotic fluid volume assessment. Unless the patient has additional indications for fetal surveillance, the patient with decreased fetal movement with a reactive nonstress test and a normal amniotic fluid volume does not appear to warrant additional testing.

Fetal acoustic stimulation in the early intrapartum period as a predictor of subsequent fetal condition

Fetal acoustic stimulation has recently received much attention in the literature. This study evaluates fetal acoustic stimulation in the early intrapartum period as a predictor of subsequent fetal condition. The study group consisted of 201 patients, approximately 60% of whom had complicated pregnancies. All were in the latent phase of labor with singleton, vertex-presenting fetuses. Gestational age ranged from 37 to 43 weeks. Fourteen of the 201 fetuses (7%) showed a nonreactive response to fetal acoustic stimulation and those fetuses were at significantly greater risk of initial and subsequent abnormal fetal heart rate patterns, meconium staining, and cesarean delivery because of fetal distress and Apgar scores less than 7 at both 1 and 5 minutes. Transient fetal heart rate decelerations after a reactive response occurred in 25% of patients; however, fetal outcome was not worse in this group. A reactive response to fetal acoustic stimulation was associated with high specificity and negative predictive values. Therefore we conclude that fetal acoustic stimulation in the early intraprtum period may discriminate the compromised from the noncompromised fetus.

Does the Onset of Neonatal Seizures Correlate with the Timing of Fetal Neurologic Injury

The onset of seizures after birth has been considered evidence of an intrapartum asphyx-ial event. The present study was undertaken to determine whether the timing of neonatal seizures after birth correlated with the timing of a fetal asphyxial event. Thus, singleton term infants diagnosed with hypoxic ischemic encephalopathy and permanent brain injury had a mean birth to seizure onset interval of 9.8 ± 17.7 (range 1-90) hours. When these infants were categorized according to their fetal heart rate (FHR) patterns, the acute group (normal FHR followed by a sudden prolonged FHR deceleration that continued until delivery) tended to have earlier seizures than infants did within the tachycardia group (normal FHR followed by tachycardia, repetitive decelerations, and diminished variability) and the preadmission group (persistent nonreactive FHR pattern intrapartum). These seizure intervals were as follows: acute, 6.6 ± 18.0 (range 1-90) hours; tachycardia, 11.1 +17.1 (range 1-61) hours; and preadmission, 11.8 +17.9 (range 1-79) hours (p<0.05). But the range varied widely and no group was categorically distinct. In conclusion, the onset of neonatal seizures after birth does not, in and of itself, appear to be a reliable indicator of the timing of fetal neurologic injury.

Fetal heart rate patterns in 423 brain-damaged infants: an update

Objective: To update our experience with the fetal heart rate (FHR) pattern of singleton term brain-damaged infants. Methods: The FHR patterns of 123 singleton term brain-damaged infants were retrospectively analyzed and compared with 300 previously published cases. Results: For these 423 cases, obstetrical care was provided from 1976 to 1998. With the exception of more recent obstetrical care, the additional 123 cases were statistically similar to the previously published 300 cases. Overall, the admission FHR patterns were reactive: 229 (54%); nonreactive: 175 (41%); bradycardic: 10 (3%); or unclassifiable: 9 (2%). In the reactive group, the FHR did the following: 1) remained reactive: 29 (13%); 2) developed an elevated baseline in association with repetitive decelerations: 107 (47%); or 3) exhibited a sudden prolonged FHR deceleration that lasted until delivery: 93 (40%). In the nonreactive group, the FHR pattern remained nonreactive at a similar baseline rate: 125 (71%); developed a progressive bradycardia: 32 (18%); or developed a prolonged deceleration that lasted until delivery: 18 (10%). Conclusion: Our retrospective review of 123 additional cases continues to demonstrate that brain-damaged fetuses manifest distinctly similar intrapartum FHR patterns that easily can be categorized and identified on the basis of the fetal admission test and subsequent changes in the baseline rate. This distinction, which covers a 22-year period, would appear to be helpful in the management of obstetrical patients in labor.